1. Field of the Invention
The invention relates in general to a scanning device, and more particularly to a scanning device having a rotatable and length-adjustable hinge for coupling a cover and a scanning body.
2. Description of the Related Art
An original medium to be scanned by a scanning device could be a piece of paper and document, or a book. It is desirable to design a scanning cover to adjust the positioning of the original mediums to be scanned with different thickness. For holding varied to-be-scanned medium, particularly a thick original medium, a hinge coupled the cover and the scanning body should be adjustable and length-changeable.
In the prior art design, the conventional hinges are mostly adjustable on the axial direction of hinges; however, they may not perform well and the application of hinge in scanning devices still has limitation. For example, a conventional hinge mainly comprises an axial rod and an openable structure with two pads. An elongated slot is vertically formed in the scanning body for receiving the axial rod of the hinge. One pad of the openable structure is fixed to the cover, and the other pad of the openable structure is mounted on the axial rod. When the scanning device is not in use, the cover is in a closed position, most part of the axial rod is positioned in elongated slot, and the pads of the openable structure are attached to each other (i.e. openable structure being in a closed condition). When a thick original medium to be scanned is placed on the scanning platen of the scanning body, the cover is raised according to the thickness of the original medium; meanwhile, the axial rod is raised as well and exposed outside the elongated slot.
However, the depth of the elongated slot is limited by (i.e. smaller than) the thickness of the scanning body. Generally, the scanning device equipped with the contact image sensor (CIS) has a thinner scanning body. The length of the axial rod of the conventional hinge is limited by the thickness of the scanning body of the scanning device. Thus, the CIS scanning device using the conventional hinge may not be able to scan the to-be-scanned medium with the considerable thickness. The conventional hinge still has the limitation in application.